New acetylenic glucosides from Bidens bipinnata LINNE. (1/21)

Two new acetylenic glucosides, 8Z-decaene-4,6-diyn-1-O-beta-D-glucopyranoside named bidenoside C, and 8E-decaene-4,6-diyn-3,10-dihydroxy-1-O-beta-D-glucopyranoside named bidenoside D, have been isolated from the aerial parts of Bidens bipinnata LINNE (Asterceae). These structures have been elucidated on the basis of spectroscopic methods.  (+info)

Synthesis and antioxidative activity of 3',4',6,7-tetrahydroxyaurone, a metabolite of Bidens frondosa. (2/21)

3',4',6,7-Tetrahydroxyaurone (1a), an aurone isolated from Bidens frondosa, and five analogues (1b-1f) were synthesized from pyrogallol in three steps. The antioxidative activity of 1a-1f was determined by the superoxide free radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging methods.  (+info)

Morphological and secretory characterization of extrafloral nectaries in plants of coastal Veracruz, Mexico. (3/21)

BACKGROUND AND AIMS: Morphological descriptions of the extrafloral nectaries (EFNs) of certain plant species are common in the literature, but they rarely relate morphology with histology, gland distribution and secretory attributes. In this study a morphological/secretory characterization of EFNs occurring on several plant species in a tropical coastal community is made and the implications of gland attributes discussed from a functional perspective. METHODS: The morphology and nectar secretion of the EFNs of 20 plant species are characterized through scanning electron microscopy, histochemical detection of reducing sugars (Fehling's reagent) and nectar volume/concentration estimates. KEY RESULTS: Sixty-five per cent of plant species in coastal communities had EFNs on vegetative structures and 35 % of species had glands on reproductive and vegetative organs. The Fabaceae is the plant family with the most species with EFNs and most diversity of gland morphologies. Four types of vascularized nectaries and four of glandular trichomes are described; sugar-secreting trichomes are characterized using Fehling's technique, and the first descriptions of unicellular and peltate trichomes functioning as EFNs are provided. Glands of ten plant species and six genera are described for the first time. Four plant species possess more than one morphological type of EFN. Eleven species have EFNs in more than one location or organ. More complex glands secrete more nectar, but are functionally homologous to the aggregations of numerous secretory trichomes on specific and valuable plant organs. CONCLUSION: Important diversity of EFN morphology was foundin the coastal plant community studied. Both vascularized and non-vascularized EFNs are observed in plants and, for the latter, previously non-existent morpho-secretory characterizations are provided with a methodological approach to study them. It is recommended that studies relating EFN attributes (i.e. morphology, distribution) with their differential visitation by insects (i.e. ants) and the cost of maintenance to the plants are carried out to understand the evolution of these glands.  (+info)

Anti-allergic Psidium guajava extracts exert an antitumor effect by inhibition of T regulatory cells and resultant augmentation of Th1 cells. (4/21)

Th1 polarization is one of the mechanisms underlying the therapeutic effects of herbal medicine. The action of anti-allergic agents from Psidium guajava (P. guajava) on T cell immunity in mice was investigated. The addition of P. guajava extracts blocked IL-10-mediated, in vitro induction of T regulatory (Tr) cells from CD4+ splenocytes of C57BL/6 mice, whereas the extracts exerted only a weak or no effect on the development of Th1 and Th2 cells. Accordingly, Tr cells were not induced from splenocytes of mice administered orally with the extracts. Furthermore, P. guajava extracts shifted the Th1/Th2 balance to a Th1 dominant status by directly attenuating Tr cell activity. In a study of tumor immunity, mice pretreated with the extracts exhibited retarded growth of s.c. inoculated B16 melanoma cells. These findings suggest that P. guajava extracts are efficacious for the prevention of tumor development by depressing Tr cells and subsequently shifting to Th1 cells.  (+info)

Screening for antimicrobial activity of ten medicinal plants used in Colombian folkloric medicine: a possible alternative in the treatment of non-nosocomial infections. (5/21)

BACKGROUND: The antimicrobial activity and Minimal Inhibitory Concentration (MIC) of the extracts of Bidens pilosa L., Bixa orellana L., Cecropia peltata L., Cinchona officinalis L., Gliricidia sepium H.B. & K, Jacaranda mimosifolia D.Don, Justicia secunda Vahl., Piper pulchrum C.DC, P. paniculata L. and Spilanthes americana Hieron were evaluated against five bacteria (Staphylococcus aureus, Streptococcus beta hemolitic, Bacillus cereus, Pseudomonas aeruginosa, and Escherichia coli), and one yeast (Candida albicans). These plants are used in Colombian folk medicine to treat infections of microbial origin. METHODS: Plants were collected by farmers and traditional healers. The ethanol, hexane and water extracts were obtained by standard methods. The antimicrobial activity was found by using a modified agar well diffusion method. All microorganisms were obtained from the American Type Culture Collection (ATCC). MIC was determined in the plant extracts that showed some efficacy against the tested microorganisms. Gentamycin sulfate (1.0 microg/ml), clindamycin (0.3 microg/ml) and nystatin (1.0 microg/ml) were used as positive controls. RESULTS: The water extracts of Bidens pilosa L., Jacaranda mimosifolia D.Don, and Piper pulchrum C.DC showed a higher activity against Bacillus cereus and Escherichia coli than gentamycin sulfate. Similarly, the ethanol extracts of all species were active against Staphylococcus aureus except for Justicia secunda. Furthermore, Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC presented the lowest MICs against Escherichia coli (0.8, 0.6 and 0.6 microg/ml, respectively) compared to gentamycin sulfate (0.9 8 g/ml). Likewise, Justicia secunda and Piper pulchrum C.DC showed an analogous MIC against Candida albicans (0.5 and 0.6 microg/ml, respectively) compared to nystatin (0.6 microg/ml). Bixa orellana L, exhibited a better MIC against Bacillus cereus (0.2 microg/ml) than gentamycin sulfate (0.5 microg/ml). CONCLUSION: This in vitro study corroborated the antimicrobial activity of the selected plants used in folkloric medicine. All these plants were effective against three or more of the pathogenic microorganisms. However, they were ineffective against Streptococcus beta hemolytic and Pseudomonas aeruginosa. Their medicinal use in infections associated with these two species is not recommended. This study also showed that Bixa orellana L, Justicia secunda Vahl. and Piper pulchrum C.DC could be potential sources of new antimicrobial agents.  (+info)

Studies of anticancer and antipyretic activity of Bidens pilosa whole plant. (6/21)

Screening of different extracts and fractions from the plant Bidens pilosa Linn. var. (Asteraceae) has been conducted using the in-vitro comet assay for anticancer and the antipyretic action, which was done with in-vivo models. The extract from whole plant was extracted with n-hexane, chloroform and methanol extract (E1 - E3). The extracts were fractioned by column chromatography method and fractioned with ethyl acetate, acetone and water (F1 - F3). All the extracts and fractions were tested for anticancer and antipyretic activity. Among extracts E1 shows remarkable anticancer activity and E3 bears maximum antipyretic activity. In the antipyretic activity, paracetamol was used as the standard test drug. The most promising material (LC50 < 1500 microg/ml) was F1 ethyl acetate fractions of methanolic extract and methanolic crude extract of whole plants. However, little correlation was observed in the degree of antipyretic activity between the test drug and standard drug. In conclusion, the extract obtained from the whole plant of Bidens pilosa showed a significant cytotoxic effect to methanolic extract against Hela cells by in vitro method and showed a comparable antipyretic activity effect to paracetamol in rabbit pyrogen test.  (+info)

Two neolignan glucosides and antihistamine release activities from Bidens parviflora WILLD. (7/21)

Two new neolignan glucosides, bidenlignasides A (1) and B (2), were isolated from the whole plant of Bidens parviflora WILLD. The structures of the two new compounds 1 and 2 established to be 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-[5E-(3-hydroxypropenyl)-3-methoxy-2-O-b eta-D-glucosyl)phenyl] propan-1-one and 3-{3-[1,3-dihydroxy-3-(4-hydroxy-3-methoxyphenyl)propyl]-4-hydroxy-5-methoxypheny l}-allyl-O-beta-D-glucuside, respectively, on the basis of spectral and chemical evidence. Compounds 1 and 2 were found to inhibit histamine release from peritoneal exudate mast cells induced by antigen-antibody reaction.  (+info)

Antioxidant activity of extracts and flavonoids from Bidens tripartita. (8/21)

Extracts from herb and flowers of Bidens tripartita L. (Asteraceae), obtained using solvents of different polarity, were studied for their radical scavenging effects. Antioxidant activities of pure flavonoids: flavanomarein (isookanin 7-O-glucoside), cynaroside (luteolin 7-O-glucoside) and luteolin, which had been isolated from this plant, were also evaluated. Radical-scavenging activity was measured by electron paramagnetic resonance (EPR) spectroscopy using stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The content of flavonoids in flower heads is half of that found in the herb; however, the extract from flowers showed that the antioxidant activity was almost two times higher there. Some extracts (n-BuOH fraction) showed long lasting radical scavenging activity and the EPR spectra were recorded in time to follow the reaction kinetics. Scavenging of DPPH showed second-order kinetics at the beginning of the assay period and later the first-order one. Different kinetics suggested the presence of polymerized and/or less active antioxidants with different scavenging mechanisms for particular polyphenolic compounds. Bur-marigold extracts are a potential source of natural antioxidants that may be used in pharmaceutical or food industry.  (+info)

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